Programmable hearing aids, such as the hearing aid disclosed in U.S. Pat. No. 4,425,481 (Mangold et al., 1984) can store a number of distinct programs, or sets of parameter values, each designed for use in different audio environments. For instance, a hearing aid with eight distinct programs could have programs for a variety of correspondingly distinct situations, such as conversing with one person in a quiet room, conversing with several persons in an otherwise fairly quiet environment, conversing with one or more persons in settings with increasing levels of background noise, walking or commuting environments with large noise variations, listening to music in a quiet room, and listening to music in a noisy environment.
In addition, the various programs in a programmable hearing aid must be customized to compensate for an individual's particular hearing deficiencies. However, some aspects of hearing aid programming are inherently subjective on the part of the user--and therefore hearing aids often must be reprogrammed several times before an optimal set of programs is found. In addition, a person's hearing characteristics may change over time, requiring adjustment of the programs stored in a programmable hearing aid. As a result, programmable hearing aids should be easily reprogrammed.
One problem associated with the design of programmable hearing aids is balancing the competing objectives of miniaturization and providing a convenient interface for connecting the device to an external programming system for reprogramming the device. In particular, a major objective in the design of hearing aids is designing very small devices, and the size of new hearing aid models is decreasing with the development of miniaturized circuitry.
In order to make a device small, it is necessary to eliminate as many components of the device as possible. In the context of the present invention, it would be desirable to eliminate the need for an external input/output port for connecting an external programming system to the hearing aid. That is, due to the limited size and surface area of miniaturized hearing aids, it is undesirable to use a portion of the device's interior volume and exterior surface area as a programming port.
In some systems proposed by hearing aid developers, a programmable hearing aid device could be programmed by remote control. In other words, a hearing aid could be programmed by wireless transmission of hearing aid parameters using either ultrasonic or radio frequency transmission techniques. However, ultrasonic and radio frequency transmission methods suffer from at least one major problem: the need for added circuitry to detect and decode the programming signals. While this problem is not insurmountable, it does increase the amount of circuitry needed in the hearing aid, and generally increases the cost of the hearing aid and the associated programming circuitry.
The present invention has the advantage of providing a direct electrical connection for programming a hearing aid, and yet it avoids the need for an external port devoted solely to the programming function. In addition, no added circuitry is needed to detect and decode programming signals.